"Oh, man! Well, how impressive is that?" Program Manager Jeff Hanley told the launch team after the spent rocket fell back to the Atlantic Ocean. "I hope you appreciate that you've accomplished a great step forward for exploration."

Said Launch Director Ed Mango: "Think about what we just did. Our first flight test, and the only thing we're waiting on is weather. That says you all did frickin' fantastic! So thank you very much."

Vapor clouds form around NASA's unmanned Ares I-X rocket as it accelerates through the region of maximum aerodynamic pressure less than a minute after liftoff Tuesday.
Ben Cooper/Spaceflight Now

The 327-foot-tall unmanned rocket roared to life at 11:30 a.m. EDT and majestically climbed away from launch complex 39B at the Kennedy Space Center atop a torrent of 5,000-degree flame and a cloud of churning exhaust.

Liftoff came three-and-a-half hours behind schedule because of overnight thunderstorms and nearby lightning strikes that required unplanned tests, along with cloudy weather that posed a risk of static charge buildups that could have interfered with communications.

The weather went in and out of limits all morning, but a break in the cloud cover gave Mango the window he needed to come out of a hold at the T-minus four-minute mark and proceed on to launch.

When the countdown hit zero, four massive hold-down bolts exploded, the booster's load of solid propellant ignited and the rocket began climbing away.

An instant after booster ignition, the rocket's nozzle moved slightly to steer the Ares I-X away from the gantry, preventing the hot exhaust from hitting launch pad structures. The maneuver was apparent to the unaided eye and the rocket stayed well away from the gantry.

Using a four-segment space shuttle solid-fuel booster as the first stage and a dummy upper stage simulator, the unusual-looking rocket - the tallest launcher since NASA's huge Saturn 5 moon rocket - cleared the gantry in about six seconds and then soared away to the East.

The Ares I-X rocket blasts off from pad 39B at the Kennedy Space Center.
Ben Cooper/Spaceflight Now

It was the first launching in NASA's post-Columbia Constellation program, which calls for development of manned and unmanned Ares rockets, Orion crew capsules and landers designed to support Antarctica-style moon bases in the 2020s.

But the Obama administration is re-evaluating NASA's manned space program and whether it makes sense to return to the moon while assessing a report from an independent panel of experts that concluded NASA did not have enough money to carry out the Constellation program.

The panel suggested it would make more sense to abandon the Ares I rocket in favor of rockets and crew capsules provide by private industry on a commercial basis. Under that approach, NASA could focus on development of the heavy lift rockets needed to carry astronauts to a variety of deep-space targets.

Given the political uncertainty in Washington, it's unclear if the Ares I rocket that Tuesday's test flight was designed to support will ever actually fly.

But NASA managers and engineers were elated to get the huge test rocket off the ground and the towering booster lived up to expectations, putting on a spectacular show for space center workers, area residents, and tourists.

"Vindication really does not describe it well," Hanley said after the flight. "It's a sense of validation that the course that we had laid out is executable. An early demonstration like this puts aside any doubt in our minds, if we had them, as to the flyability of this particular design.

"We have a design that will do the country service, if it is put into service," he said. "The performance of the vehicle was very pleasing, to put it mildly."

Twenty seconds after liftoff, the rocket reached its maximum thrust of 3.16 million pounds of push with an internal pressure of 895 pounds per square inch.

The flight plan called for the rocket's nozzle to move back and forth 0.12 degrees 34 seconds after liftoff in a "programmed test input" to collect data on the stiffness of the vehicle and how it responded to dynamic changes.

The results of the nozzle deflections were too subtle to be visible to the unaided eye and the rocket appeared to stay solidly on course as it accelerated through the sound barrier 39 seconds after liftoff.

Long-range tracking cameras showed the rocket making only slight rolling motions about its long axis as small roll control rockets fired to maintain the proper orientation. Roll control was a question mark early on in the rocket's development, but engineers said it was not a problem in flight.

Another "programmed test input" - moving the nozzle by 0.12 degrees - presumably began at 55 seconds into flight. Five seconds after that, the Ares I-X was expected to experience maximum dynamic pressure of 850 pounds per square foot, subjecting the booster to the greatest stress it would experience in flight.

A 0.35 degree programmed test input was planned for 75 seconds into flight with a final 1-degree side-to-side yaw maneuver scheduled for 93.6 seconds.

The rocket accelerated to a peak velocity of about 4.5 times the speed of sound, reaching an altitude of 25.2 miles. At that point, when the rocket's thrust fell to less than 40,000 pounds of push, an explosive charge fired to separate the first stage from the dummy upper stage.

A wide-angle shot of the Ares I-X rocket climbing away through a partly cloudy sky.
Ben Cooper/Spaceflight Now

An instant later, eight upward-firing rockets at the base of the booster ignited to back the first stage away from the second, a maneuver clearly visible in long-range tracking camera views.

But in a departure from the expected flight program, the dummy second stage went into a flat tumble as it continued along its ballistic trajectory instead of maintaining a nose-forward orientation. The dummy upper stage rose to a maximum altitude of about 150,000 feet before arcing over and plunging back to Earth 150 miles east of the space center.

In a final major test, three 150-foot-wide parachutes were designed to deploy to lower the spent first-stage booster casing to the Atlantic Ocean where a NASA recovery ship was standing by to tow it back to Port Canaveral. A camera on the rocket showed a smaller drogue parachute deployed, but video stopped moments later and the main chutes were not seen.

But the recovery ship quickly located the booster and a NASA spokesman said the crew of an aircraft flying over the floating rocket later said all three parachutes were visible in the water. An initial assessment, sources said, indicated normal blistering on the rocket and a dent of unknown origin in the aft segment.

"We completely met our success criteria, in fact we blew them away," said Mission Manager Bob Ess. "The first one was to roll out (to the launch pad), obviously we did that one. Clear the pad, we did that without a problem. Fly the intended flight path, we certainly did that, we confirmed that. And the last one was to learn from the flight.

"So far, we're on a path to learn a lot. The separation seemed a little different than we predicted as far as how the upper stage reacted after separation. So right there's an opportunity for us to jump in and figure out what was different in the actual flight from our models. So, hugely successful."

It will take engineers several weeks to complete a quick-look analysis of data from more than 700 sensors that measured pressures, stresses, temperatures, and other factors throughout the flight. But the initial results indicated no major problems.